1. Field of the Invention
The present invention relates to an exercising device and more particularly to such a device operable for leg exercise which minimizes variation in the muscular force required through an exercising stroke and which eliminates those hazards encountered in the use of prior art exercising device which create a risk of strain and injury to the operator.
2. Description of the Prior Art
Pursuant to 37 C.F.R. 1.97 and 1.98 and the Rules Of Practice In Patent Cases, the applicant hereby makes of record the following prior art patents, copies of which are enclosed:
______________________________________ 1,966,848 Charters July 17, 1934 2,397,054 Segalla Mar. 19, 1946 650,009 Galleret Feb. 7, 1951 2,809,624 Becher et al. Oct. 15, 1957 3,128,094 Wolf Apr. 7, 1964 3,387,843 Chandler June 11, 1968 3,465,592 Perrine Sept. 9, 1969 3,784,194 Perrine Jan. 8, 1974 ______________________________________
In addition the applicant wishes to make of record the attached copies of two photographs showing exercising devices representing the closest such devices currently on the market to the applicant's invention insofar as the applicant is aware.
The Charters U.S. Pat. No. 1,966,848 discloses a combined exercising and amusement device.
The Segalla U.S. Pat. No. 2,397,054 discloses an exercising apparatus.
The Galleret U.S. Pat. No. 650,009 discloses a physical culture apparatus using an hydraulic cylinder.
The Becher et al. U.S. Pat. No. 2,809,624 discloses a missile firing trainer device using a compressed gas cylinder.
The Wolf U.S. Pat. No. 3,128,094 discloses an exerciser with hydraulically interconnected chinning bar and foot support.
The Chandler U.S. Pat. No. 3,387,843 discloses an exercise machine in which the user pushes or pulls against a resisting force produced by a pnuematic cylinder operating in conjunction with compressed air.
The Perrine U.S. Pat. No. 3,465,592 discloses an isokinetic exercise process and apparatus operable for leg exercise.
The Perrine U.S. Pat. No. 3,784,194 shows a bilateral reciprocal isokinetic exerciser operable for leg exercise.
The copies of two photographs attached hereto reveal leg exercising machines currently on the market which utilize stacks of weights as the resistance force.
Commercially available exercising devices possess certain characteristics of operation which create a risk of injury to the operator and which prevent realization of the optimum muscular exertion for a given period of use. Nearly all commercial exercising devices, whether for use in leg exercises or otherwise, employ a stack of weights as the resistance force. Typically the operator selects the number of weights to be lifted and then operates the device by exerting force against a movable member to lift the number of weights selected. Because of the inertia of rest of the weight stack, initial movement can be achieved only by exerting considerably more muscular force than the average of the forces exerted throughout the exercising stroke. However, once movement of the weight stack has been initiated, inertia of motion greatly reduces the amount of force which must be applied to continue movement of the weight stack through the stroke. Similarly, if the operator moves quickly enough, the return stroke of the exercising member can be accomplished with little or no resistance force due to inertia causing the weight stack to lag behind movement of the exercising member. While the average of the forces exerted against the exercising member throughout the stroke may be approximately that most suited to the exercising operation desired, the actual force exerted at any given point along the stroke is most commonly either substantially greater or substantially less than the optimum.
The problems encountered in such prior art devices are particularly acute where leg exercisers are concerned. Leg exercises are, of course, undertaken to develop or to maintain development of leg muscles and particularly those of the thigh. Four muscles located on the front and sides of the thigh known as the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius form a muscle group which is normally the subject of development exercises. However, it is well known that serious injury can occur in the ligaments and tendons of the knee area in exercises of this type. Unfortunately, prior art exercising devices tend to create strain on these structures of the knee during exercise of the thigh muscles. Not only does the uneven requirement of muscular exertion during an exercising stroke produce strain in the knee, but such devices in themselves appear to create a significant portion of the stress in the knee area rather than in the muscles which are the subject of the exercising activity. Furthermore, where the weight stack lags behind movement of the exercising member to the start position, an extremely dangerous situation is presented. If the operator exerts force to slow the return of the exercising member so that the weight stack catches up with the member, sudden and severe strain can be placed on muscles, tendons and ligaments. This risk of injury is intolerable in hospital environments were the devices are used for therapeutic purposes such as after knee surgery.
Therefore, it has long been known that it would be desirable to have an exercising device which requires the exertion of relatively uniform muscular force throughout an exercising stroke so as to obtain optimum benefit from a given period of exercise, which reduces to an absolute minimum the risk of injury using such an exercising device, and which places the burden of the exercising activity on those muscles which are the target rather than placing strain on tendons, ligaments or other connective tissue.